The present invention relates generally to infrared (IR) thermometers, more particularly to an infrared thermometer and method for measuring the temperature of an object and most particularly to an infrared thermometer for measuring the temperature of an object that has a rotatable protective housing operatively connected to the IR component housing.
Infrared thermometry has been available for many applications based on a variety of designs. Typically, these early thermometer designs were developed for testing temperature of difficult to reach objects or objects operating at fairly high temperatures--such as the interior of an industrial oven. Such exotic environments were well suited to infrared detection due to the large temperature differences between ambient and the subject object and for the reason that there were few alternatives.
More recently, infrared temperature detection techniques have found application in clinical temperature measurement and specifically the diagnostic measurement of patient body measurement by detecting the infrared emissions radiating from the tympanic membrane of the ear. This membrane is found to comprise a temperature highly correlated to actual body temperature and its measurement with infrared detection techniques has become a highly accurate reading taken in a matter of seconds.
The present invention application is directed to improvements to the prior IR thermometers disclosed in U.S. Pat. No. 4,797,840 and its reissue RE. 34,789, and U.S. Pat. No. 5,368,038 both assigned to the assignee of the present invention, the disclosure of each is hereby incorporated by reference.
As disclosed in the above mentioned patents, the temperature of an object, such as the human body, has been determined by using a contact thermometer or by measuring the naturally radiated energy from the body such as the radiated energy in the far infrared range. The infrared radiation is directly related to temperature of the object and has been used to determine the temperature of the body.
Medical thermometers are useful in the diagnosis and treatment of many diseases. In the past, measurement of a patient's body temperature had been most commonly performed by conventional mercury thermometers. Disadvantages of such thermometers included the amount of time required to obtain accurate readings, a minute or more, and that they needed to be disinfected before each use. Later, electronic thermometers became popular because they required far less time to obtain an accurate temperature reading and the probe of the electronic thermometer was commonly inserted into a protective disposable cover before use. Such electronic thermometers are rapidly reusable and are generally sanitary when used with sanitary sheaths. However, obtaining an accurate reading of a patient's temperature still required as much as 30 seconds, since the temperature is measured through the sanitary sheath that must equilibrate to the patient's temperature. Such thermometers were also generally used orally or rectally.
The auditory canal and the tympanic membrane are also known to be useful for measurement of a patient's internal body temperature. Electronic thermometers for measuring the temperature of the tympanic membrane by directly contacting the tympanic membrane are well known and has been described in many U.S. Patents. However, such devices have proven to have certain disadvantages such as causing discomfort to the patient, inserting the probe without a sheath, thus requiring sterilization between uses in order to decrease the time required for an accurate temperature, or utilizing a sheath or speculum for sanitary purposes while generally increasing the time required to obtain an accurate measurement.
More recently, infrared thermometers avoided the necessity of contacting the location at which temperature is actually being measured and were designed for use in measuring the patient's temperature from the auditory canal and/or from the tympanic membrane. As described in the above-mentioned patents, an infrared detector receives infrared radiation from the auditory canal through an internally polished truncated cone that serves as a shield and an insulator, so that temperature readings are only taken from the auditory canal.
As shown in FIG. 1, a representative schematic of a prior medical infrared thermometer 10 is shown in an exploded view. This thermometer comprises a self-contained, battery powered unit that has probe 12 adapted for insertion into an ear canal, short of the tympanic membrane. Housing member 14 of thermometer 10 is shaped for convenient handling by a user. The thermometer has an actuation button 16 that when depressed triggers the device to take a reading of the infrared radiation from within the ear canal.
Probe 12 at the front of the thermometer is of a shape and dimension that is compatible with the profile of a human ear canal. Before insertion into the canal, probe 12 is covered by protective probe cover 18 that is conventionally fabricated of a thin polymer material that is substantially transparent to light in the near and far infrared spectral ranges.
As shown, electronic circuity 22 is connected to the IR assembly 20 via a cable 24. A power supply 26 in the form of a nine (9) volt battery is connected to the circuit 22 and is typically contained in housing 14. Other conventional components are typically used to complete the encasement of the IR Thermometers' components inside housing 14.
The purpose of the front portion of the probe is to gather infrared light from the tympanic membrane and surrounding tissue. An infrared sensor assembly 20 is positioned remote from the end of the probe, being positioned inside housing member 14 of thermometer 10.
In the past, when not in use, infrared thermometers were typically stored in a second, separate protective unit or a substantially hollow housing member (not shown, but see U.S. Pat. No. 4,602,642 issued to O'Hara et al. as one specific example) . During the periods of nonuse, the infrared thermometer having the exposed probe 12 was inserted into the second, separate hollow protective housing such that the probe 12 was encased inside the hollow portion of the second, separate housing member. Additionally, this particular type of separate hollow protective housing member typically included storage provisions for the protective covers for the probe.
Having a totally separate protective housing member for the IR thermometer has proven both inconvenient and expensive. A separate protective housing member is inconvenient because it is not always in near proximity to the user and because it can become separated from the IR thermometer during use. With the two separate housing members used with the prior IR thermometers, after use, the user had to locate the second housing member and insert the IR thermometer probe into the hollow second, separate, protective/storage housing member.
Additionally, the cost of a separate second housing member for protectively storing the infrared thermometer was nearly, if not equal to, the cost of the first housing member less the IR components housed therein. Further, since the separate second housing member occasionally became lost or misplaced, the inconvenience and cost of replacement of second housing members was not inconsequential.
While the above described IR thermometers were clear advances in the art, they were somewhat complex in that they included two separate, housing members, were more expensive to manufacture than believed necessary and had high replacement part costs.
Thus, there is a need for a new improved infrared thermometer and method for measuring the temperature of an object. Such improved infrared thermometer should have a single housing member and include provisions for the protective storage of the IR thermometer during non-use periods; should be more economically manufactured and should eliminate the need for a second, separate housing member used as a separate protective/storage housing and, thus, the need for replacing the second, separate protective/storage housing member(s) when lost.